In the panoramic tomographic radiography technique, a layer of certain thickness of the object is visible on the X-ray film. This is the so-called picture layer the form, position and thickness of which can be varied by the geometry involved with the radiography of the object. Normally in this photo technique, the radiation source and the film move relative to the patient who remains stationary during the radiography. The desired point or zone to be radiographed is pictured accurately on the film when the film speed is the same as the speed of the projection spot on the surface of the film to be pictured.
The known arrangements for turning or moving an X-ray film tend to be rather complicated so as to be easily moved or upset out of adjustment. However, in attempts to simplify such arrangements by the use of a cylindrical type film cassette, the obtained results are not entirely satisfactory and in many instances tend to be excessive in cost. In this connection, reference is made to U.S. Pat. Nos. 2,684,446, 2,798,958, 3,536,913 and 3,636,349.
The object of this invention is to develop a motion mechanism for the X-ray film of straight film cassette which is of a simple construction, inexpensive in cost and efficient and practical in operation. Such parts as cog wheels and geared rods, gear belts and wires are eliminated so as to achieve a vibration-free film motion having dependable operation over a long service life.